1. Field of the Invention
The present invention relates to packages for semiconductor chips or other electronic devices, and leadframes for making the packages.
2. Description of Related Art
A typical package for a semiconductor chip includes an internal metal leadframe, which functions as a substrate for the package. The leadframe includes a central die pad and a plurality of leads that radiate outward from the die pad. A hardened, insulative encapsulant material covers the die, die pad, and an inner portion of each of the leads.
The semiconductor chip is mounted on the die pad and is electrically connected to the leads. In particular, the chip includes a plurality of bond pads, each of which is electrically connected by a bond wire or the like to an inner end segment that is at an inner end of one of the leads. An exposed portion of each lead extends outward from the encapsulant, and serves as an input/output terminal for the package.
In the market for semiconductor packaging today, there is a trend toward increased package functionality. This trend includes increasing the number of leads provided in a package. At the same time, there is a trend toward smaller, more compact packages. In keeping with these trends, ever finer leads and inner end segments are required. It can be difficult to meet this industry need while also keeping the cost of the package within reason. Limitations on known methods for making leads and inner end segments, such as chemical etching or mechanical stamping, also makes meeting industry needs difficult, as these methods have inherent limitations as to how fine and dense the leads and the inner end segments can be made. At the same time, the inner end segments must be wide enough to serve as a site for electrical connection to a wire or some other conductor that electrically connects the respective inner end segment to the chip. Accordingly, an improved method of making a leadframe is desirable.